An unusually-wide human bregmatic Wormian bone: anatomy, tomographic description, and possible significance.

Supernumerary ossicles (or Wormian bones) of the cranial vault are formations associated with insufficient rate of suture closure, and regarded as "epigenetic" and "hypostotic" traits. These bones rest along sutures and/or fill fontanelles of the neonatal skull. In this autoptic report of a 66-year-old Caucasian woman, a peculiar supernumerary bone is described, unusual size and shape, filling completely the bregmatic fontanelle. The skull was CT-scanned through coronal sections at 80 kV and 60 mA, with a slice thickness of 1.0 mm and a resolution of 0.35 mm/pixel. Segmentation and 3D rendering were computed using MIMICS 7.0 (digital endocast). The bone was pentagonal and remarkably large, more on the exocranial surface than on the endocranial one, involving both tables and diploe of the vault. This feature might represent a wedge to completion of the vault architecture. Considering the functional and structural matrix of cranial morphogenesis, this case displays the possibility of discrete diversification of the ossification centres, as well as the relative stability of the structural skull matrix in response to discrete changes.

Ultrastructural dynamics of the human endometrium from 14 to 22 weeks of gestation.

In order to elucidate the ultrastructural dynamics of endometrium differentiation, uterine samples of fetuses aged 14 to 22 weeks of gestation (WG) were analyzed. Samples were processed for light (LM), transmission (TEM) and field-emission scanning electron microscopy (FE-SEM). Initial stratification of the uterine wall occurred at 14 WG: endometrial, myometrial, and perimetrial primordia were identified. At this age, the endometrial epithelium was simple columnar to pseudostratified and consisted of microvillous cells. Blood capillaries developed mainly in the stroma and between the myometrium and perimetrium primordia. At 18-20 WG the endometrial epithelium became clearly pseudostratified, with active ciliogenesis and a predominance of microvillous cells. Primordia of tubular glands were present at 20 WG. Microvillous cells still predominated in the endometrial epithelium at 21-22 WG and showed morphological features of apoptosis. The endometrial stroma at this stage was organizing into a thick lamina propria provided with subepithelial capillary plexuses. However, the stroma was formed by still undifferentiated mesenchymal cells during the whole period of study. Our data showed that the epithelial differentiation and distribution in the uterus occur in the human fetus in a similar way as in the adult. The above events are likely the expression of an early developmental patterning and related to future reproductive processes, such as the regulation of gamete passage and blastocyst implantation. Because the structure of the adult uterus is determined by the degree of paramesonephric duct fusion, septum absorption, and differentiation of the uterine primordial layers, our study may contribute toward clarifying to normal urogenital development.